Mate in 3: rook to d7 (d1·4)
c9-25646naming tag (square·N)Opens in the app if installed, otherwise downloads the APK.
The tactical motive
Chess960 twist: use the unusual starting setup of the pieces.
Mate in 3: a forced sequence that ends in checkmate.
Difficulty 1630 ShuffleRating — for advanced tacticians.
White to move — find the best continuation
How to recognize this tactic
In Chess960 the pieces start on unfamiliar squares, so tactics appear earlier and from unusual angles. Do not trust classical patterns — read the actual lines of the bishops, the rooks and the queen from where they really stand in this position.
In a mate in three every move must be forcing; the defender should never get a free tempo. Find the check or threat that herds the king, calculate the single defence to each, and confirm the net closes on the third move.
General method: before you move, list the forcing candidates — every check, every capture, every direct threat — and calculate those first. The solution to a tactic is almost always among them.
Position on the board
White: king c1, queen a8, rook d1, bishop g5, pawn b2 c3 g4 b6.
Black: king f7, queen e4, bishop h2, pawn c6 d7 h7.
8 white and 6 black pieces are on the board; the puzzle position arises after move 35.
The position in numbers
White are ahead by 6 points of material (21 against 15; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.
The white king stands on c1, the black king on f7.
It is White to move on move 35, with 39 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 4 pawns, Black 3. Files fully open (no pawns of either colour): a, e, f — natural highways for the rooks and queen. Half-open for White: d, h.
The White king has 1 empty squares to step to right now — the fewer they are, the closer a mating net.
Solution & explanation
Main line
35. Rxd7+ Qe7 36. Rxe7+ Kg6 37. Qg8#
Why it works
- Best move. rook to d7 is exactly what the engine plays (#2).
- Spot on — rook to e7 (#1).
- Precise: queen to g8 is the top choice (#).
- The line ends in a forced mate in 3.
- If instead Qe7, then Rxe7+ and you win the queen.
Move by move
- 35. Rxd7+ — rook to d7 (capture) with check
- Qe7 — queen to e7
- 36. Rxe7+ — rook to e7 (capture) with check
- Kg6 — king to g6
- 37. Qg8# — queen to g8 and it is checkmate
Types in this puzzle
Mate in 3
A forced checkmate in three moves.
Mate in three is a forced staircase: each of your moves narrows the opponent's choices, and the third one ends the game. Look for the start among checks and sacrifices — quiet first moves are rare in mating problems, but deliciously sneaky. Keep the tree in your head: every defense gets its own branch. Do not stop calculating after move two — see the final mating picture with your own eyes.
Win the pinned piece
The pinned piece cannot run — attack it again and win it.
A pinned piece cannot flee, which means you can win it outright by attacking it one more time. Count attackers against defenders: if you outnumber them, the piece is yours. The best extra attacker is a pawn, since it costs less than anything it might capture. Do not rush the capture — build up the pressure first, then harvest.
About this position
These pieces come from starting position #703.
SP-703 · BastionGuard — The king starts one file off-centre, on c or f, with neither knight in a corner.
The king starts on c1, the rooks on a1 and f1, the queen on b1.
The king already stands on c1, so castling long moves only the rook, from a1 to d1.
A bishop starts in the corner on h1: it has a single diagonal, which the g-pawn unlocks, running out to a8.
One second-rank pawn starts with no defender at all: e2.
The setup belongs to the BastionGuard family; read right to left it becomes position 448.
The engine's main line opens with e4, putting a pawn straight into the centre.
Morozov Balance Index: 69 of 100 — class B — balanced. Engine evaluation of the starting position: +21 centipawns for White (depth 44, 400 000 000 nodes).
Explore position #703Provenance
Mined from the project's engine self-play games.
Pack 012 · SP-703
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